Multiple-unit tube



MULTIPLE UNIT TUBE Filed April 29, 1927 INVENTOR 'SIEGTMUND LOEWE fia [dam/a ORNEY Patented Jan. 24, 1933 V A r i i UNITED srA'rss PATENT emu:

SIEGMUND LOEWE, or BERLIN, rRInnEnau, GE MANY, ASSIGNQR To RA IO CORPORATION OF AMERICA, A CORPORATION DFDELAWARE MULTIPLE- UNIT TUBE Application filed April 29, 1927, Serial No. 187,650, and in Germany July 19, 192 6.

This invention relates to a vacuum tube, odes are denoted by 2, 3,4; the gridsor'co'n and more particularly to a multiple-unit tube. trol electrodes by 5, 6,7 the plates oranodes Multiple-unit tubes in the sense as h-ereinby 8, 9, 10." 11 and 12 1n Fig. l ar-e plate after used are vacuum bulbs in which, within or anode resistances, 13 and 14 are grid leaks,

* one and the same vacuous space, at least two and 15' and 16' are coupling, that'i'sj, transfer amplifier systems belonging to different condensers. p

stages are arranged, each system compris ng Now,' this form of arrangement of mul afilamentary, a grid or control electrode and tiple-unit tubes does not permitselectiv ty,

a plate or anode, said systems being connected The potential variations supplied to the in inside the same vacuous space by coupling put lead 17 to grid 5 reappearin aperiodicalmeans such as resistances and capacities. ly amplified form in "the consumer" circuit Multiple-unit tubes of this kind have here connected with the plate According to tofore been known only in the form of rethe present inventiom such a multiple-unit sistance-coupled amplifier tubes, in which tube is equipped in a way asshown, "for ex 15 the coupling between the first plate and the ample, in Figure '2 to allow'of selectivity. second grid was effected by the aid of high- Although the' coupling' condenser 15 and ohmic resistances with the intermediary of a the leak resistance 131are enclosed inside the transfer condenser. It has been found that same vacuous space,inthisenibo'diment, such multiple-unit tubes result in a very high first plate ,is separately brought" outfit-.118.

aperiodic amplification, but that this, under Inithis manner, it is possible to useany concertain circumstances, is associated with a venientelement as the; alternating-current drawback. Since the aperiodic amplification resistance for the plate circuit, for inst nce; with approximately the same effectiveness eX- a tuned circuit or a 'tick l'er coil (reaction tends over a relatively large frequency range coil), which in well known manner is in re or band, it results that in the output circuit generativelcoupling relationship with the 75 of such resistance-coupled multiple-unit systuned input circuit connected with the grid tems very great amplifications are obtained, lead 17 to grid 5, and which is brought to the but at the same time also very little selectivjoint plate battery. In this manner, to be ity. But it is desirable to preserve the adsure, purely aperiodic amplification can be 39 vantages offered by multiple-unit systems, insured by inserting outside the tube a pure without having to accomplish amplification ohmic resistance which is connected with the in a purely aperiodic manner as is predomplate battery. But it is now feasible to ininantly true of capacity-resistance-coupled fiuence and shape the frequencycharacteris- I arrangements. tic of the tube in any desired manner, more According to the disclosures of this invenparticularly, to enhance selectivity by the tion, it is an object of this invention to provide insertion of tuned circuits or by the provision ways and means whereby selectivity is 'renof back-coupling. Instead of bringing out dered feasible in the rear of the first system, the first plate, this selectivity may, of course, or, in cases where greater numbers of ambe also eifected with one of the higher stages plifier stages are dealt with, ahead of the save the last. In the case of the last plate, :90, last system. action as regards selectivity of the amplifier The invention shall be explained more fully device is not practically possible. According by reference to the accompanying drawing. to whether the first, second, or third plate Figure 1 shows a diagrammatic view of a is brought out, the first or second, etc., plate I three-unit or three-stage tube of the design resistance is to be omitted. In this manner, 95

customary heretofore, and the advantages of multiple-unit tubes arcin- Figure 2 diagrammatically shows a tube sured without the circuit advantages of sepbuilt accordmg to my invention. arate tube systems having to be sacrificed.

Inside acommon vacuous space 1 is a three I claim as my invention: V stage amplifier system. The filamentary cath- 1. A multiple unit tube enclosing a plu- 109 rality of capacity-coupled amplification stages, each stage comprising an anode, a conof the next succeeding stage, and a leak re- I sistance connected to the control electrode of trol electrode anda. cathode, and an external lead directly connected to the anode of a stage preceding the last.

2. A multiple unit! tube enclosing a plurality of capacity-coupled amplification stages, each stage comprising, an anode, a

control electrode and a cathode, and an external lead directly connected'to the anode of the first stage.

rality of amplification stages, each stage comprising an anode, a control electrode and a cathode, the anode in a stage preceding the last stage having an external lead directly conn.ected thereto, a resistance connected to the anode'in the next succeeding stage, a coupling condenser connected between the anode of each stage and the control electrode each stage except the said preceding stage, said coupling condensers and resistances being enclosed within the tube.

4. A multi-stage thermionic amplifier,

comprising the combination with an evacuated envelope, of several amplifier stages V housed within said envelope, each stage comprismg an anode,a control electrode and a cathode,an external lead directly connected to the anode of the first stage, an impedance connected to the anodeof the nextsucceeding stage, a coupling condenser between the anode of each stage and the control electrode of the next stage, and an impedance connected to the control electrode of each'stage except the first, said coupling condensers and impedances being enclosed within the envelope.

, SIEGMUND LOEWVE.

3. A multiple un1t tube enclosing a. 'plu- I 

